Optical imaging system

ABSTRACT

An optical imaging system includes a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a negative refractive power, a fourth lens having a negative refractive power, and a fifth lens having a positive refractive power. The first to fifth lenses are sequentially disposed from an object side to an imaging plane. One or more lenses among the first to fifth lenses are formed using a glass material.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.15/498,926 filed on Apr. 27, 2017, which claims the benefit under 35U.S.C. § 119(a) of Korean Patent Application No. 10-2016-0177430, filedon Dec. 23, 2016 in the Korean Intellectual Property Office, the entiredisclosure of which is incorporated herein by reference for allpurposes.

BACKGROUND 1. Field

The following description relates to a telescopic optical imaging systemincluding five lenses.

2. Description of Related Art

Telescopic optical imaging systems capable of capturing images ofdistant objects may be significantly large. In detail, in terms oftelescopic optical imaging systems, the (TL/f) ratio of the overalllength TL of a telescopic optical imaging system to the overall focallength f may be greater than or equal to 1. Thus, it may be difficult tomount telescopic optical imaging systems in small electronic devices,such as portable terminals.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

In one general aspect, an optical imaging system includes a first lenshaving a positive refractive power, a second lens having a negativerefractive power, a third lens having a negative refractive power, afourth lens having a negative refractive power, and a fifth lens havinga positive refractive power, sequentially disposed from an object sideto an imaging plane. One or more lenses among the first to fifth lensesare formed using a glass material.

The first lens of the optical imaging system may have opposing convexsurfaces along an optical axis. The second lens of the optical imagingsystem can have a convex object-side surface along an optical axis and aconcave image-side surface along the optical axis. The third lens of theoptical imaging system may have opposing concave surfaces along anoptical axis. The fourth lens of the optical imaging system can haveopposing concave surfaces along an optical axis. The fifth lens of theoptical imaging system may have a concave object-side surface along anoptical axis and a convex image-side surface along the optical axis.

The refractive index of the first lens of the optical imaging system maybe less than or equal to 1.52. The refractive index of the second lensof the optical imaging system can be greater than or equal to 1.7. Therefractive index of the third lens of the optical imaging system may begreater than or equal to 1.8. The refractive index of the second lensand a refractive index of the fourth lens can each be lower than therefractive index of the third lens.

In another general aspect, an optical imaging system includes a firstlens, a second lens, a third lens, a fourth lens, and a fifth lens,sequentially disposed from an object side to an imaging plane. One ormore lenses among the first to fifth lenses are formed using a glassmaterial.

The optical imaging system may satisfy the expression 0.7<TL/f<1.0,where TL represents a distance from an object-side surface of the firstlens to an imaging plane, and f represents an overall focal length ofthe optical imaging system. The half angle of view of the opticalimaging system can be less than or equal to 20°.

The first to third lenses of the optical imaging system may be formedusing a glass material. The optical imaging system can satisfy theexpression Nd1<Nd2<Nd3, where Nd1 represents a refractive index of thefirst lens, Nd2 represents a refractive index of the second lens, andNd3 represents a refractive index of the third lens. The refractiveindex of the second lens and the refractive index of the third lens mayeach be greater than or equal to 1.7.

In another general aspect, an optical imaging system includes a firstlens, a second lens, a third lens, a fourth lens, and a fifth lens. Thefirst to fifth lenses are sequentially disposed from an object side toan imaging plane, wherein at least one of the first to fifth lenses areaspheric and formed using a glass material, wherein the first lenscomprises a greatest Abbe number in the optical imaging system, andwherein the third lens comprises a greatest refractive index in theoptical imaging system.

The first to third lenses of the optical imaging system may be formedusing a glass material. The optical imaging system can satisfy theexpression Nd1<Nd2<Nd3, where Nd1 represents a refractive index of thefirst lens, Nd2 represents a refractive index of the second lens, andNd3 represents a refractive index of the third lens, and wherein therefractive index of the third lens is greater than or equal to 1.8. TheAbbe number of the first lens of the optical imaging system may begreater than or equal to 65. Other features and aspects will be apparentfrom the following detailed description, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an optical imaging system according to a firstexample.

FIG. 2 is a set of graphs illustrating aberration curves of the opticalimaging system illustrated in FIG. 1.

FIG. 3 is a set of graphs illustrating transverse curves of the opticalimaging system illustrated in FIG. 1.

FIG. 4 is a diagram of an optical imaging system according to a secondexample.

FIG. 5 is a set of graphs illustrating aberration curves of the opticalimaging system illustrated in FIG. 4.

FIG. 6 is a set of graphs illustrating transverse curves of the opticalimaging system illustrated in FIG. 4.

FIG. 7 is a rear view of a portable terminal including an opticalimaging system mounted therein according to an example.

FIG. 8 is a cross-sectional view of the portable terminal illustrated inFIG. 7.

Throughout the drawings and the detailed description, the same referencenumerals refer to the same elements where applicable. The drawings maynot be to scale, and the relative size, proportions, and depiction ofelements in the drawings may be exaggerated for clarity, illustration,or convenience.

DETAILED DESCRIPTION

Hereinafter, examples will be described with reference to the attacheddrawings. Examples provide an optical imaging system capable ofcapturing images of distant objects, while being mounted in a smallterminal.

The disclosure may, however, be exemplified in many different forms andshould not be construed as being limited to the specific embodiments setforth herein. Rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the disclosure to those skilled in the art.

Throughout the specification, it will be understood that when anelement, such as a layer, region or wafer (substrate), is referred to asbeing “on,” “connected to,” or “coupled to” another element, it can bedirectly “on,” “connected to,” or “coupled to” the other element, orother elements intervening therebetween may be present. In contrast,when an element is referred to as being “directly on,” “directlyconnected to,” or “directly coupled to” another element, there may be noelements or layers intervening therebetween. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

Although terms such as “first,” “second,” and “third” may be used hereinto describe various components, regions, or sections, these components,regions, or sections are not to be limited by these terms. Rather, theseterms are only used to distinguish one component, region, or sectionfrom another component, region, or section. Thus, a first component,region, or section referred to in examples described herein may also bereferred to as a second component, region, or section without departingfrom the teachings of the examples.

The articles “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. The terms“comprises,” “includes,” and “has” specify the presence of statedfeatures, numbers, operations, members, elements, and/or combinationsthereof, but do not preclude the presence or addition of one or moreother features, numbers, operations, members, elements, and/orcombinations thereof.

Due to manufacturing techniques and/or tolerances, variations of theshapes shown in the drawings may occur. Thus, the examples describedherein are not limited to the specific shapes shown in the drawings, butinclude changes in shape that occur during manufacturing.

The features of the examples described herein may be combined in variousways as will be apparent after an understanding of the disclosure ofthis application. Further, although the examples described herein have avariety of configurations, other configurations are possible as will beapparent after an understanding of the disclosure of this application.

In the present specification, a first lens refers to a lens closest toan object or a subject of which an image is captured. A fifth lensrefers to a lens closest to an imaging plane or an image sensor. In thepresent specification, an entirety of a radius of curvature, athickness, a distance from an object-side surface of a first lens to animaging plane (TL), a half diagonal length of the imaging plane (IMGHT), and a focal length of a lens is indicated in millimeters (mm). Aperson skilled in the relevant art will appreciate that other units ofmeasurement may be used. Further, in embodiments, all radii ofcurvature, thicknesses, OALs (optical axis distances from the firstsurface of the first lens to the image sensor), a distance on theoptical axis between the stop and the image sensor (SLs), image heights(IMGHs) (image heights), and back focus lengths (BFLs) of the lenses, anoverall focal length of an optical system, and a focal length of eachlens are indicated in millimeters (mm). Likewise, thicknesses of lenses,gaps between the lenses, OALs, TLs, SLs are distances measured based onan optical axis of the lenses.

In a description of a form of a lens, a surface of a lens being convexmeans that an optical axis portion of a corresponding surface is convex,while a surface of a lens being concave means that an optical axisportion of a corresponding surface is concave. Therefore, in aconfiguration in which a surface of a lens is described as being convex,an edge portion of the lens may be concave. In a manner the same as thecase described above, even in a configuration in which a surface of alens is described as being concave, an edge portion of the lens may beconvex. In other words, a paraxial region of a lens may be convex, whilethe remaining portion of the lens outside the paraxial region is eitherconvex, concave, or flat. Further, a paraxial region of a lens may beconcave, while the remaining portion of the lens outside the paraxialregion is either convex, concave, or flat. In addition, in anembodiment, thicknesses and radii of curvatures of lenses are measuredin relation to optical axes of the corresponding lenses.

In accordance with illustrative examples, the embodiments described ofthe optical system include five lenses with a refractive power. However,the number of lenses in the optical system may vary in some embodiments,for example, between two to five lenses, while achieving one or moreresults and benefits described below. Also, although each lens isdescribed with a particular refractive power, a different refractivepower for at least one of the lenses may be used to achieve the intendedresult.

An optical imaging system includes a plurality of lenses. For example,the optical imaging system may include the first lens, a second lens, athird lens, a fourth lens, and a fifth lens, sequentially disposed in adirection from an object side to an imaging plane.

The optical imaging system includes a lens formed using a glassmaterial. However, not all lenses in the optical imaging system areformed using a glass material. For example, a portion of lenses in theoptical imaging system are formed using a glass material, while theremainder of lenses are formed using a plastic material.

The first lens has a refractive power. For example, the first lens has apositive refractive power. The first lens has a convex surface. In anembodiment, the first lens has a convex object-side surface.

The first lens has an aspherical surface. For example, both surfaces ofthe first lens are aspherical. The first lens may be formed using amaterial having a relatively high degree of light transmittance andexcellent workability. As an example, the first lens may be formed usinga glass material. However, a material of the first lens is not limitedto glass. The first lens has a refractive index. In an embodiment, arefractive index of the first lens is greater than or equal to 1.0 andless than 1.52.

The first lens has a focal length. As an example, a focal length of thefirst lens is within a range of 2.5 mm to 3.0 mm.

The second lens has a refractive power. For example, the second lens hasa negative refractive power. The second lens has a convex surface. In anembodiment, the second lens has a convex object-side surface.

The second lens has an aspherical surface. For example, both surfaces ofthe second lens are aspherical. The second lens may be formed using amaterial having a relatively high degree of light transmittance andexcellent workability. As an example, the second lens may be formedusing a glass material. However, a material of the second lens is notlimited to glass. The second lens has a refractive index greater thanthat of the first lens. In an embodiment, a refractive index of thesecond lens is greater than or equal to 1.7 and less than 2.0.

The second lens has a focal length. As an example, a focal length of thesecond lens is within a range of −12.0 mm to −8.0 mm.

The third lens has a refractive power. For example, the third lens has anegative refractive power. The third lens has a concave surface. In anembodiment, the third lens has a concave image-side surface.

The third lens has an aspherical surface. For example, both surfaces ofthe third lens are aspherical. The third lens may be formed using amaterial having a relatively high degree of light transmittance andexcellent workability. As an example, the third lens is formed using aglass material. However, a material of the third lens is not limited toglass. The third lens has a refractive index greater than that of thesecond lens. In detail, the refractive index of the third lens isgreater than or equal to 1.8 and less than 2.2.

The third lens has a focal length. As an example, a focal length of thethird lens is within a range of −0.6 mm to −3.0 mm.

The fourth lens has a refractive power. For example, the fourth lens hasa negative refractive power. The fourth lens has a concave surface. Inan embodiment, the fourth lens has a concave object-side surface.

The fourth lens has an aspherical surface. For example, both surfaces ofthe fourth lens are aspherical. The fourth lens may be formed using amaterial having a relatively high degree of light transmittance andexcellent workability. As an example, the fourth lens is formed using aplastic material. However, a material of the fourth lens is not limitedto plastic. The fourth lens has a refractive index lower than that ofthe third lens. In an embodiment, the refractive index of the fourthlens is greater than or equal to 1.0 and less than 1.6.

The fourth lens includes an inflection point. For example, the fourthlens includes one or more inflection points formed on an image-sidesurface. The fourth lens has a focal length. As an example, a focallength of the fourth lens is within a range of −6.0 mm to −3.0 mm.

The fifth lens has a refractive power. For example, the fifth lens has apositive refractive power. The fifth lens has a convex surface. In anembodiment, the fifth lens has a convex image-side surface.

The fifth lens has an aspherical surface. For example, both surfaces ofthe fifth lens are aspherical. The fifth lens may be formed using amaterial having a relatively high degree of light transmittance andexcellent workability. As an example, the fifth lens is formed using aplastic material. However, a material of the fifth lens is not limitedto plastic. The fifth lens has a refractive index greater than that ofthe fourth lens. In an embodiment, the refractive index of the fifthlens is greater than or equal to 1.6 and less than 1.7.

The fifth lens has a focal length. As an example, a focal length of thefifth lens is within a range of 30 mm to 60 mm.

Hereinafter, components that do not include a lens will be described.The optical imaging system includes an image sensor. A surface of theimage sensor forms an imaging plane. The imaging plane may have asubstantially rectangular shape. However, the imaging plane is notlimited to having a rectangular shape. For example, the imaging plane isformed in a square shape. Also, the image sensor may be configured toimplement high resolution.

The optical imaging system includes a filter. For example, the opticalimaging system includes a filter configured to block infrared light. Thefilter may be formed using a glass material. In an embodiment, thefilter is provided as transparent glass on which an infrared cut-offfilm is formed. A refractive index of the filter may be substantiallygreater than or equal to 1.5. The filter having the characteristicsdescribed above may be interposed between a fifth lens and the imagesensor.

The optical imaging system includes a stop configured to adjust anamount of light. In detail, the stop is interposed between a third lensand a fourth lens and adjusts an amount of light incident on the imagesensor.

An aspherical surface of a lens in the optical imaging system may beexpressed using Formula 1.

$\begin{matrix}{Z = {\frac{{cr}^{2}}{1 + \sqrt{1 - {\left( {1 + k} \right)c^{2}r^{2}}}} + {Ar}^{4} + {Br}^{6} + {Cr}^{8} + {Dr}^{10} + {Er}^{12} + {Fr}^{14} + {Gr}^{16} + {Hr}^{18} + {Jr}^{20}}} & \left\lbrack {{Formula}\mspace{14mu} 1} \right\rbrack\end{matrix}$

In Formula 1, c represents an inverse of a radius of curvature of alens, k represents a conic constant, r represents a distance from acertain point on an aspherical surface of the lens to an optical axis, Ato J represent aspherical constants, and Z (or SAG) represents adistance between the certain point on the aspherical surface of the lensat the distance r and a tangential plane meeting the apex of theaspherical surface of the lens.

The optical imaging system satisfies the following ConditionalEquations:

0.7<TL/f<1.0  [Conditional Equation 1]

Nd1<1.52  [Conditional Equation 2]

1.7<Nd2  [Conditional Equation 3]

1.8<Nd3  [Conditional Equation 4]

Nd2<Nd3,Nd4<Nd3  [Conditional Equation 5]

FOV/2<20  [Conditional Equation 6]

In the Conditional Equations, TL represents a distance from theobject-side surface of a first lens to an imaging plane, f represents anoverall focal length of the optical imaging system, Nd1 represents arefractive index of the first lens, Nd2 represents a refractive index ofa second lens, Nd3 represents a refractive index of the third lens, Nd4represents a refractive index of the fourth lens, and FOV represents anoverall angle of view of the optical imaging system.

The optical imaging system having the configuration described above maybe mounted in a portable terminal, a small camera, front and rearsurveillance cameras of an automobile, a closed-circuit television(CCTV), or the like.

Subsequently, an optical imaging system according to various exampleswill be described. First, the optical imaging system according to afirst example will be described with reference to FIG. 1. An opticalimaging system 100, according to the example, includes a first lens 110,a second lens 120, a third lens 130, a fourth lens 140, and a fifth lens150.

The first lens 110 has a positive refractive power and opposing convexsurfaces. The second lens 120 has a negative refractive power, a convexobject-side surface, and a concave image-side surface. The third lens130 has a negative refractive power and opposing concave surfaces. Thefourth lens 140 has a negative refractive power and opposing concavesurfaces. The fifth lens 150 has a positive refractive power, a concaveobject-side surface, and a convex image-side surface.

First lens 110 has a relatively low refractive index. For example, therefractive index of first lens 110 is less than or equal to 1.52. Secondlens 120 and third lens 130 have a relatively high refractive index. Forexample, the refractive index of second lens 120 is greater than orequal to 1.7, while the refractive index of third lens 130 is greaterthan or equal to 1.8. Fourth lens 140 and fifth lens 150 have arefractive index lower than that of third lens 130. For example, therefractive index of fourth lens 140 is less than or equal to 1.6, whilethe refractive index of fifth lens 150 is less than or equal to 1.7.

First lens 110 has the highest Abbe number in optical imaging system100. For example, an Abbe number of first lens 110 is greater than orequal to 65. Second lens 120 and third lens 130 have a relatively lowAbbe number. For example, Abbe numbers of second lens 120 and third lens130 are less than or equal to 30. Fourth lens 140 has a relatively highAbbe number. For example, an Abbe number of fourth lens 140 is greaterthan or equal to 50. Fifth lens 150 has the lowest Abbe number in theoptical imaging system. For example, an Abbe number of fifth lens 150 isless than or equal to 25.

Each lens of optical imaging system 100 has a focal length. For example,a focal length of first lens 110 is 2.705 mm, a focal length of secondlens 120 is −10.13 mm, a focal length of third lens 130 is −4.349 mm, afocal length of fourth lens 140 is −4.337 mm, and a focal length offifth lens 150 is 37.285 mm.

Optical imaging system 100 is configured to include lenses formed usingdifferent materials. For example, first lens 110, second lens 120, andthird lens 130 are formed using a glass material, while fourth lens 140and fifth lens 150 are formed using a plastic material.

Optical imaging system 100 further includes a filter 160, an imagesensor 170, and a stop ST. Filter 160 is interposed between fifth lens150 and image sensor 170, while stop ST is interposed between third lens130 and fourth lens 140.

An optical imaging system having the configuration described above hasaberration characteristics as illustrated by the graphs in FIGS. 2 and3. Table 1 lists lens characteristics of optical imaging system 100according to the example, while Table 2 lists aspherical characteristicsof the optical imaging system according to the example.

TABLE 1 First Example FOV/2 = 16.64 f = 8.700 TL = 6.40 Sur- face Radiusof Thickness/ Effective Refractive Abbe No. Curvature Distance RadiusIndex Number S1 First 1.5077 0.9590 1.250 1.512 68.0 S2 Lens −13.340.0810 1.130 S3 Second 21.271 0.2510 1.060 1.755 27.5 S4 Lens 5.59590.3890 0.950 S5 Third −11.950 0.2400 0.780 2.001 29.1 S6 Lens 6.91631.7490 0.710 S7 Fourth −3.9238 0.2400 1.150 1.544 56.0 S8 Lens 6.04700.7650 1.460 S9 Fifth −21.5714 0.9540 2.140 1.632 23.4 S10 Lens −11.45470.0220 2.260 S11 Filter infinity 0.2100 2.430 S12 infinity 0.5830 2.620S13 Imaging infinity 0.0000 Plane

TABLE 2 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 K −0.3224 −99.000 44.5110 −5.5906−11.950 6.9163 −3.9238 0.0000 80.6084 0.0000 A 0.0088 0.0940 0.0463−0.0147 0.0000 0.0000 −0.8393 −0.1306 −0.1440 −0.2220 B 0.0119 −0.03230.1270 0.3100 0.1554 0.2079 −0.1012 0.3487 0.2618 0.2118 C −0.0381−0.2165 −1.0053 −2.0972 −0.0041 0.0050 0.0774 −0.7032 −0.2153 −0.1042 D0.0955 0.4920 2.8585 7.9100 −0.8329 −0.7424 −0.0634 0.8513 0.1064 0.0317E −0.1276 −0.5535 −4.9445 −18.653 3.7058 4.3623 −0.4282 −0.6482 −0.0338−0.0070 F 0.0957 0.3612 5.4629 27.4949 −10.102 −14.753 1.3727 0.31330.0070 0.0013 G −0.0376 −0.1290 −3.7103 −24.485 14.8725 24.5575 −1.8594−0.0932 −0.0009 −0.0002 H 0.0059 0.0198 1.4098 12.0503 −8.6473 −10.8101.3365 0.0155 0.0001 0.0000

An optical imaging system according to a second example will bedescribed with reference to FIG. 4. An optical imaging system 200,according to the example, includes a first lens 210, a second lens 220,a third lens 230, a fourth lens 240, and a fifth lens 250.

The first lens 210 has a positive refractive power and opposing convexsurfaces. The second lens 220 has a negative refractive power, a convexobject-side surface, and a concave image-side surface. The third lens230 has a negative refractive power and opposing concave surfaces. Thefourth lens 240 has a negative refractive power and opposing concavesurfaces. The fifth lens 250 has a positive refractive power, a concaveobject-side surface, and a convex image-side surface.

First lens 210 has a relatively low refractive index. For example, therefractive index of first lens 210 is less than or equal to 1.52. Secondlens 220 and third lens 230 have relatively high refractive indices. Forexample, the refractive index of second lens 220 is greater than orequal to 1.7, while the refractive index of third lens 230 is greaterthan or equal to 1.8. Fourth lens 240 and fifth lens 250 have refractiveindices lower than that of third lens 230. For example, a refractiveindex of fourth lens 240 is less than or equal to 1.6, while arefractive index of fifth lens 250 is less than or equal to 1.7.

First lens 210 has the highest Abbe number in optical imaging system200. For example, an Abbe number of first lens 210 is greater than orequal to 65. Second lens 220 and third lens 230 have substantiallyrelatively low Abbe numbers. For example, Abbe numbers of second lens220 and third lens 230 are less than or equal to 30. Fourth lens 240 hasa relatively high Abbe number. For example, an Abbe number of fourthlens 240 is greater than or equal to 50. Fifth lens 250 has the lowestAbbe number in the optical imaging system. For example, an Abbe numberof fifth lens 250 is less than or equal to 25.

Each lens of optical imaging system 200 has a focal length. For example,a focal length of first lens 210 is 2.675 mm, a focal length of secondlens 220 is −10.53 mm, a focal length of third lens 230 is −4.382 mm, afocal length of fourth lens 240 is −4.287 mm, and a focal length offifth lens 250 is 51.752 mm.

Optical imaging system 200 is configured to include lenses formed usingdifferent materials. For example, first lens 210, second lens 220, andthird lens 230 are formed using a glass material, while fourth lens 240and fifth lens 250 are formed using a plastic material.

Optical imaging system 200 further includes a filter 260, an imagesensor 270, and a stop ST. Filter 260 is interposed between fifth lens250 and image sensor 270, while stop ST is interposed between third lens230 and fourth lens 240.

An optical imaging system having the configuration described above hasaberration characteristics as illustrated by the graphs in FIGS. 5 and6. Table 3 lists lens characteristics of optical imaging system 200according to the example, while Table 4 lists aspherical characteristicsof optical imaging system 200 according to the example.

TABLE 3 Second Example FOV/2 = 16.64 f = 8.700 TL = 6.38 Sur- faceRadius of Thickness/ Effective Refractive Abbe No. Curvature DistanceRadius Index Number S1 First 1.4890 0.9430 1.250 1.512 68.0 S2 Lens−13.41 0.0830 1.140 S3 Second 25.089 0.2530 1.070 1.755 27.5 S4 Lens6.0111 0.3670 0.960 S5 Third −11.411 0.2400 0.790 2.001 29.1 S6 Lens7.2003 1.7220 0.710 S7 Fourth −3.7601 0.2400 1.150 1.544 56.0 S8 Lens6.2812 0.7690 1.460 S9 Fifth −21.2400 0.9620 2.150 1.632 23.4 S10 Lens−13.1033 0.0220 2.270 S11 Filter infinity 0.2100 2.430 S12 infinity0.5830 2.620 S13 Imaging infinity 0.0000 Plane

TABLE 4 S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 K −0.3167 −99.000 41.1599 −4.90400.0000 0.0000 −2.5685 0.0000 80.6084 0.0000 A 0.0092 0.0947 0.0462−0.0143 0.1640 0.2180 −0.0971 −0.1325 −0.1573 −0.2353 B 0.0121 −0.03200.1270 0.3100 −0.0376 −0.0671 0.0588 0.3918 0.28380 0.2234 C −0.0379−0.2164 −1.0049 −2.0968 −0.7096 −0.1163 0.1282 −0.7840 −0.2329 −0.1082 D0.0956 0.4920 2.8589 7.9100 3.4579 0.4098 −1.1242 0.9315 0.1153 0.0311 E−0.1276 −0.5534 −4.9444 −18.652 −10.400 1.5895 2.6982 −0.6963 −0.0365−0.0060 F 0.0957 0.03612 5.4629 27.4952 17.5614 −19.213 −3.3562 0.33030.0074 0.0009 G −0.0376 −0.1290 −3.7103 −24.486 −14.472 61.9052 2.3381−0.0962 −0.0009 −0.0001 H 0.0059 0.0198 1.4098 12.0503 3.0496 −86.068−0.8616 0.0157 0.0001 0.0000

Hereinafter, a portable terminal including an optical imaging systemmounted therein, according to an example, will be described withreference to FIGS. 7 and 8. A portable terminal 10 includes a pluralityof camera modules 20 and 30. A first camera module 20 includes a firstoptical imaging system 101, configured to capture an image of a subjectat a short distance. A second camera module 30 includes second opticalimaging systems 100 and 200, configured to capture an image of a distantsubject.

First optical imaging system 101 includes a plurality of lenses. Forexample, first optical imaging system 101 includes four or more lenses.First optical imaging system 101 is configured to capture images ofobjects at a short distance. In detail, first optical imaging system 101may have a relatively wide angle of view of 50° or more, while a (TL/f)ratio is greater than or equal to 1.0.

Second optical imaging systems 100 and 200 include a plurality oflenses. For example, second optical imaging systems 100 and 200 mayinclude five lenses. Second optical imaging systems 100 and 200 may beprovided as one optical imaging system among optical imaging systems, asin the first and second examples described above. Second optical imagingsystems 100 and 200 may be configured to capture an image of a distantobject. In detail, second optical imaging systems 100 and 200 have anangle of view of 40° or less, while a (TL/f) ratio is less than 1.0.

First optical imaging system 101 and second optical imaging systems 100and 200 may be substantially equal in size. In detail, an overall lengthL1 of first optical imaging system 101 is substantially the same as anoverall length L2 of second optical imaging systems 100 and 200.Alternatively, a ratio (L1/L2) of the overall length L1 of first opticalimaging system 101 to the overall length L2 of second optical imagingsystems 100 and 200 may be from 0.8 to 1.0. In embodiments, a ratio(L2/h) of the overall length L2 of second optical imaging systems 100and 200 to a thickness h of portable terminal 10 may be less than orequal to 0.8.

As set forth above, according to examples, an optical imaging systemcapable of capturing a distant image and being mounted in a smallterminal may be provided. While this disclosure includes specificexamples, it will be apparent after an understanding of this disclosurethat various changes in form and details may be made in these exampleswithout departing from the spirit and scope of the claims and theirequivalents. The examples described herein are to be considered in adescriptive sense only, and not for purposes of limitation.

Descriptions of features or aspects in each example are to be consideredas being applicable to similar features or aspects in other examples.Suitable results may be achieved if the described techniques areperformed in a different order, and/or if components in a describedsystem, architecture, device, or circuit are combined in a differentmanner, and/or replaced or supplemented by other components or theirequivalents. Therefore, the scope of the disclosure is defined not bythe detailed description, but by the claims and their equivalents, andall variations within the scope of the claims and their equivalents areto be construed as being included in the disclosure.

What is claimed is:
 1. An optical imaging system, comprising: a firstlens comprising a positive refractive power; a second lens comprising anegative refractive power; a third lens comprising a negative refractivepower; a fourth lens comprising a negative refractive power; and a fifthlens comprising a positive refractive power, wherein the first to fifthlenses are sequentially disposed from an object side to an imagingplane, and wherein one or more lenses among the first to fifth lensesare formed using a glass material.
 2. The optical imaging system ofclaim 1, wherein the first lens has opposing convex surfaces along anoptical axis.
 3. The optical imaging system of claim 1, wherein thesecond lens has a convex object-side surface along an optical axis and aconcave image-side surface along the optical axis.
 4. The opticalimaging system of claim 1, wherein the third lens has opposing concavesurfaces along an optical axis.
 5. The optical imaging system of claim1, wherein the fourth lens has opposing concave surfaces along anoptical axis.
 6. The optical imaging system of claim 1, wherein thefifth lens has a concave object-side surface along an optical axis and aconvex image-side surface along the optical axis.
 7. The optical imagingsystem of claim 1, wherein a refractive index of the first lens is lessthan or equal to 1.52.
 8. The optical imaging system of claim 1, whereina refractive index of the second lens is greater than or equal to 1.7.9. The optical imaging system of claim 1, wherein a refractive index ofthe third lens is greater than or equal to 1.8.
 10. The optical imagingsystem of claim 1, wherein the refractive index of the second lens and arefractive index of the fourth lens are each lower than the refractiveindex of the third lens.
 11. An optical imaging system, comprising: afirst lens, a second lens, a third lens, a fourth lens, and a fifthlens, sequentially disposed from an object side to an imaging plane,wherein one or more lenses among the first to fifth lenses are formedusing a glass material.
 12. The optical imaging system of claim 11,wherein the optical imaging system satisfies the following expression:0.7<TL/f<1.0, where TL represents a distance from an object-side surfaceof the first lens to an imaging plane, and f represents an overall focallength of the optical imaging system.
 13. The optical imaging system ofclaim 11, wherein a half angle of view is less than or equal to 20°. 14.The optical imaging system of claim 11, wherein the first to thirdlenses are formed using a glass material.
 15. The optical imaging systemof claim 11, wherein the optical imaging system satisfies the followingexpression:Nd1<Nd2<Nd3, where Nd1 represents a refractive index of the first lens,Nd2 represents a refractive index of the second lens, and Nd3 representsa refractive index of the third lens.
 16. The optical imaging system ofclaim 11, wherein the refractive index of the second lens and therefractive index of the third lens are each greater than or equal to1.7.
 17. An optical imaging system, comprising: a first lens, a secondlens, a third lens, a fourth lens, and a fifth lens, wherein the firstto fifth lenses are sequentially disposed from an object side to animaging plane, wherein at least one of the first to fifth lenses areaspheric and formed using a glass material, wherein the first lenscomprises a greatest Abbe number in the optical imaging system, andwherein the third lens comprises a greatest refractive index in theoptical imaging system.
 18. The optical imaging system of claim 17,wherein the first to third lenses are formed using a glass material. 19.The optical imaging system of claim 17, wherein the optical imagingsystem satisfies the expression:Nd1<Nd2<Nd3 where Nd1 represents a refractive index of the first lens,Nd2 represents a refractive index of the second lens, and Nd3 representsa refractive index of the third lens, and wherein the refractive indexof the third lens is greater than or equal to 1.8.
 20. The opticalimaging system of claim 17, wherein the Abbe number of the first lens isgreater than or equal to 65.